Cellulose ester composition

ABSTRACT

A cellulose ester composition having good thermoplasticity and including: (A) a cellulose ester and (B) a plasticizer, wherein the plasticizer of the component (B) includes at least one kind selected from adipic acid esters respectively represented by the following formulae (I), (II) and (III).

TECHNICAL FIELD

The present invention relates to a cellulose ester composition.

BACKGROUND ART

Since cellulose esters such as cellulose acetate generally have a poorthermoplasticity, they are usually used in compositions containingplasticizers.

JP-A 10-306175 is an invention related to a fatty acid celluloseester-based resin composition, and describes that a known plasticizercan be blended therein (Paragraph 0023).

JP-A 2005-194302 is an invention related to a resin composition composedof a cellulose ester with an average degree of substitution of 2.7 orless, a plasticizer and a filler, and describes that a phosphate esteror the like can be used as the plasticizer (Paragraph 0020).

JP-A 2008-260895 is an invention of a film including a polylactic acidresin composition obtained by blending benzyl alkyl diglycol adipate,which is effective as a plasticizer for polylactic acid resins. In theExamples, benzyl methyl diglycol adipate is used (Paragraph 0034).

SUMMARY OF THE INVENTION

An object of the present invention is to provide a cellulose estercomposition having a high thermoplasticity.

As a solution for the problems, the present invention provides acellulose ester composition including: (A) a cellulose ester and (B) aplasticizer, wherein the plasticizer of the component (B) contains atleast one selected from adipic acid esters respectively represented bythe following formulae (I), (II) and (III).

As the solution for the problems, the present invention provides acellulose ester composition including: (A) a cellulose ester and (B) aplasticizer, wherein the plasticizer of the component (B) includes atleast one selected from adipic acid esters represented by the followingformulae (IV), (V) and (VI).

In the general formulae (IV), (V) and (VI), n is an integer of 0-5representing a degree of condensation, which includes the cases wheren=0 and n=1-5. “Me” represents a methyl group.

The cellulose ester composition of the present invention has a highthermoplasticity.

DETAILED DESCRIPTION OF THE INVENTION

<Component (A)>

The cellulose ester of the component (A) used for the composition of thepresent invention is a known one (for example, those described in JP-A10-306175 and JP-A 2005-194302), and can include cellulose acetate,cellulose propionate, cellulose butyrate, cellulose acetate propionateand cellulose acetate butyrate.

Additionally, the cellulose ester of the component (A) can includepolycaprolactone-grafted cellulose acetate, acetyl methyl cellulose,acetyl ethyl cellulose, acetyl propyl cellulose, acetyl hydroxyethylcellulose, acetyl hydroxypropyl cellulose, and the like.

The cellulose ester of the component (A) is preferably a celluloseacetate having an average degree of substitution of 2.7 or less.

A polymerization degree of the cellulose ester of the component (A) is100-1000, preferably 100-500 as a viscosity-average polymerizationdegree.

<Component (B)>

The plasticizer of the component (B) used for the composition of thepresent invention includes ones selected from adipic acid estersrepresented by the following formulae (I), (II) and (III). Note that the“Me” represents a methyl group.

Among the adipic acid esters represented by the formulae (I), (II) and(III), a plasticizer containing only the adipic acid ester of theformula (I), a plasticizer containing a mixture of the adipic acidesters of the formulae (I) and (II), or a plasticizer containing amixture of the adipic acid esters of the formulae (I), (II) and (III)can be used as the plasticizer of the component (B).

When the plasticizer containing a mixture of the adipic acid esters ofthe formulae (I) and (II) is used as the component (B),

a content ratio of the adipic acid ester of the formula (I) ispreferably 35-80% by mass, more preferably 40-80% by mass, and

a content ratio of the adipic acid ester of the formula (II) ispreferably 65-20% by mass, more preferably 60-20% by mass.

When the plasticizer containing a mixture of the adipic acid esters ofthe formulae (I), (II) and (III) is used as the component (B),

a content ratio of the adipic acid ester of the formula (I) ispreferably 35-80% by mass, more preferably 40-75% by mass,

a content ratio of the adipic acid ester of the formula (II) ispreferably 15-50% by mass, more preferably 20-50% by mass, and

a content ratio of the adipic acid ester of the formula (III) ispreferably 5-35% by mass, more preferably 5-30% by mass.

As to the composition of the present invention, a plasticizer includingan adipic acid ester selected from adipic acid esters represented by thefollowing the general formulae (IV), (V) and (VI) can also be used asthe plasticizer of the component (B).

In the general formulae (IV), (V) and (VI), n is an integer of 0-5representing a degree of condensation, which includes the cases wheren=0 and n=1-5.

Each of the adipic acid esters represented by the general formulae (IV),(V) and (VI) contained in the plasticizer of the component (B) is amixture of the adipic acid esters of n=0 and the adipic acid esters ofn=1-5.

An average degree of condensation (N) of the adipic acid estersrepresented by the general formulae (IV), (V) and (VI) ranges 0<N≤5,preferably 0<N≤4, more preferably 0<N≤3.

When the plasticizer of the component (B) contains the adipic acidesters represented by the general formulae (IV), (V) and (VI), a contentratio of the adipic acid esters of n=0 to the total amount of the adipicacid esters represented by the general formulae (IV), (V) and (VI) ispreferably 10% by mass or more, more preferably 10-70% by mass, andfurther more preferably 15-60% by mass.

Note that the adipic acid esters of n=0 are the adipic acid esters ofthe above-described formulae (I), (II) and (III).

As the adipic acid esters of the formulae (I), (II) and (III) in theadipic acid esters of n=0 contained in the adipic acid estersrepresented by the general formulae (IV), (V) and (VI), there can beused:

adipic acid esters containing only adipic acid esters of the formula(I);

adipic acid esters containing a mixture of adipic acid esters of theformulae (I) and (II); and

adipic acid esters containing a mixture of adipic acid esters of theformulae (I), (II) and (III).

When the adipic acid ester of n=0 is a mixture of the adipic acid estersof the formulae (I) and (II),

a content ratio of the adipic acid ester of the formula (I) ispreferably 35-80% by mass, more preferably 40-80% by mass, and

a content ratio of the adipic acid ester of the formula (II) ispreferably 65-20% by mass, more preferably 60-20% by mass.

When the adipic acid ester of n=0 is a mixture of the adipic acid estersadipic acid esters of the formulae (I), (II) and (III),

a content ratio of the adipic acid ester of the formula (I) ispreferably 35-70% by mass, more preferably 40-70% by mass,

a content ratio of the adipic acid ester of the formula (II) ispreferably 15-50% by mass, more preferably 15-40% by mass, and

a content ratio of the adipic acid ester of the formula (III) ispreferably 15-35% by mass, more preferably 15-30% by mass.

As to the content ratios of the component (A) and the component (B) inthe composition of the present invention, the content ratio of thecomponent (B) is 1-50 parts by mass, preferably 5-30 parts by massrelative to 100 parts by mass of the component (A).

The composition of the present invention can contain known thermoplasticresins in accordance with the uses.

The known thermoplastic resins can include styrene-based resins such asABS resins and AS resins; polycarbonate-based resins; polyolefin-basedresins such as polyethylene and polypropylene; polyamide-based resinssuch as polyamide 6, polyamide 66, polyamide 610 and polyamide 612;acrylic resins; methacrylic resins; polyester-based resins;polyacetal-based resins; polyphenylene sulfide-based resins; and thelike.

A content ratio of the known thermoplastic resins to the total amounttogether with the cellulose ester of the component (A) is preferably 40%by mass or less, more preferably 20% by mass.

The composition of the present invention can contain not only theplasticizer of the component (B) but also known plasticizers.

For example, the composition may contain:

aromatic carboxylate esters (phthalic acid di-C1-12 alkyl esters such asdimethyl phthalate, diethyl phthalate, dibutyl phthalate, dihexylphthalate, dioctyl phthalate and di-2-ethylhexyl phthalate; phthalicacid C1-6 alkoxy C1-12 alkyl esters such as dimethoxyethyl phthalate;phthalic acid C1-12 alkylaryl-C1-3 alkyl esters such as butyl benzylphthalate; C1-6 alkylphthalyl C2-4 alkylene glycolates such asethylphthalyl ethylene glycolate and butylphthalyl butylene glycolate;trimellitic acid tri-C1-12 alkyl esters such as trimethyl trimellitate,triethyl trimellitate, trioctyl trimellitate and tri-2-ethylhexyltrimellitate; pyromellitic acid tetra-C1-12 alkyl esters such astetraoctyl pyromellitate; and the like),

fatty acid esters (adipic acid esters such as dibutyl adipate, dioctyladipate, butoxyethoxyethylbenzyl adipate and dibutoxyethoxyethyladipate; azelaic acid esters such as diethyl azelate, dibutyl azelateand dioctyl azelate; sebacic acid esters such as dibutyl sebacate anddioctyl sebacate; butyl oleate; methylacetyl ricinoleate: and the like),

lower fatty acid esters of polyhydric alcohols (glycerin, trimethylolpropane, pentaerythritol, sorbitol, and the like) (triacetin,diglycerine tetraacetate, and the like),

glycol esters (dipropylene glycol dibenzoate, and the like),

citric acid esters (acetyl tributyl citrate, and the like)

amides (N-butyl benzene sulfonamide, and the like)

ester oligomers (caprolactone oligomer, and the like) and the like.

These plasticizers can be used alone or in a combination of two or morekinds thereof.

The composition of the present invention can further contain a filler.

The filler may include a fibrous filler and a non-fibrous filler(powder-particle filler, plate-like filler or the like) and can beexemplified by a filler described in JP-A 2005-194302, Paragraphs0025-0032.

A content ratio of the filler is preferably 5-50 parts by mass, morepreferably 5-40 parts by mass, and further more preferably 5-30 parts bymass relative to 100 parts by mass of the cellulose ester of thecomponent (A).

The composition of the present invention can contain stabilizers such asan epoxy compound described in Paragraphs 0035-0042 in JP-A 2005-194302,and organic acids, thioether or phosphorous acid ester compoundsdescribed in Paragraphs 0043-0052.

The composition of the present invention may include commonly usedadditives, for example other stabilizers (e.g. antioxidants, ultravioletabsorbers, heat stabilizers, light stabilizers, and the like), colorants(dye, pigment, and the like), flame retardants, antistatic agents,lubricants, anti-blocking agents, dispersants, fluidizer, drippinginhibitors, antimicrobial agents and the like, in accordance with theuses.

As to the composition of the present invention, each component may beprepared using a mixer such as a tumbler mixer, a Henshel mixer, aribbon mixer or a kneader, by a dry or wet process.

Furthermore, after premixing by the mixer, there can be applied a methodof kneading the composition by an extruder such as a single screw ortwin screw extruder and preparing the resultant product into pellets, ora method of melting and kneading the composition by a kneader such as aheating roller and Banbury mixer for preparation.

The composition of the present invention can be molded into variousmolded articles by injection molding, extrusion molding, vacuum molding,profile molding, foam molding, injection press, press molding, blowmolding, gas injection molding, and the like.

The composition of the present invention can be used for, for example,individual parts, housings and the like such as in the OA/householdelectrical appliance field, the electric/electronic field, thetelecommunication equipment field, the sanitary field, the transportvehicle field like automobiles, the housing-related field such asfurniture and building materials, and the general merchandise field.

EXAMPLES Examples and Comparative Example

As samples for measuring mass reduction rates under heat and humidityconditions, the cellulose acetate of the component (A) shown in Table 2,the plasticizer of the component (B) shown in Tables 1 and 2, andcomponents for comparison shown in Table 2 were charged into abatch-type kneader “LABO PLASTOMILL” manufactured by TOYO SEIKI Co.,Ltd., and were kneaded under the conditions of a predeterminedtemperature of 210° C., a blade rotation rate of 100 r/m, and a kneadingtime of 5 minutes to thereby give each composition.

Component (A)

Cellulose acetate: Trade name “L50” manufactured by Daicel Corporation,substitution degree: 2.5, viscosity-average polymerization degree: 180

Component (B) Production Example 1 (Plasticizer Shown in B-1 of Table 1)

146.1 g (1 mol) of adipic acid, 129.8 g (1.2 mol) of benzyl alcohol,144.2 g (1.2 mol) of diethylene glycol monomethyl ether, 0.95 g ofp-toluenesulfonic acid and 120 g of toluene were charged into afour-neck flask of 1 liter provided with a thermometer, a stirrer, acondenser and a water dividing unit, and were refluxed and caused toreact for 8 hours, while water produced was drained by using the waterdividing unit.

After neutralization with 2.9 g of sodium carbonate and water, theremoval of the residual solvent and residual alcohol by water washing,desolvation and steam distillation gave the target product having thecomposition shown in B-1 of Table 1, at a yield of 96.9%.

Note that content ratios of adipic acid esters represented by theformulae (I), (II) and (III) were measured by gas chromatography (GC).The measurement conditions are shown below.

Column: DB-1, 30 m, 0.32 mmØ, film: 0.25 μm

Temperature: Sample vaporizing chamber 200° C.

Column thermostat bath: from 50° C. (5 min.), increased at 15° C./min.to 250° C. (10 min.)

Detector: 280° C.

Carrier gas: He (Pressure at an inlet: 100 kPa)

Detector: FID (H₂ 40.0 mL/min., Air 400.0 mL/min.)

Split 54

Injection volume: 0.5 μl (Sample: about 0.2 g/10 ml acetone)

Production Example 2 (Plasticizer Shown in B-2 of Table 1)

A target product shown in B-2 of Table 1 was obtained at a yield of92.3% in the same way as that of Production example 1 except that theamount of benzyl alcohol was changed to 77.9 g (0.72 mol), and theamount of diethylene glycol monomethyl ether was changed to 201.8 g(1.68 mol).

Production Example 3 (Plasticizer Shown in B-3 of Table 1)

146.1 g (1 mol) of adipic acid, 120.2 g (1 mol) of diethylene glycolmonomethyl ether, 0.95 g of p-toluenesulfonic acid and 100 g of toluenewere charged into a four-neck flask of 0.5 liter provided with athermometer, a stirrer, a condenser and a water dividing unit, and wererefluxed and caused to react for 4.5 hours, while water produced wasdrained by using the water dividing unit. The reaction liquid was cooledto 5° C., and a precipitated and unreacted adipic acid was filtered outand removed.

The filtrate was returned to the flask, to which 28.3 g of sodiumcarbonate and 170 g of water were added, and caused to react at 70° C.for 30 minutes. The reaction solution was left at rest to separate intoan aqueous layer and an oil layer, and the dehydration of the aqueouslayer gave 145.9 g of sodium salt.

73.4 g (0.58 mol) of benzyl chloride, 12.2 g of benzyltriethylammoniumchloride and 130 g of toluene were added to the obtained sodium salt,and caused to react at 80° C. for 2 hours. Then, water washing,neutralization, desolvation and steam distillation were carried out togive 146.3 g of the compound represented by the formula (I) as a targetproduct.

Production Example 4 (Plasticizer Shown in B-4 of Table 1)

146.1 g (1 mol) of adipic acid, 288.2 g (2.4 mol) of diethylene glycolmonomethyl ether, 0.95 g of p-toluenesulfonic acid and 120 g of toluenewere charged into a four-neck flask of 1 liter provided with athermometer, a stirrer, a condenser and a water dividing unit, and wererefluxed and caused to react for 8 hours, while water produced wasdrained by using the water dividing unit.

After neutralization with 2.9 g of sodium carbonate and water, theremoval of the residual solvent and residual alcohol by water washing,desolvation and steam distillation gave the compound represented byformula (II), at a yield of 94.6%.

The mixing of the resultant product with the compound represented by theformula (I) obtained in Production example 3 in the composition shown inB-4 of Table 1 gave a target product.

Production Example 5 (Plasticizer Shown in B-5 of Table 1)

291.9 g (2.0 mol) of adipic acid, 48.2 g (0.8 mol) of ethylene glycol,0.12 g of tetraisopropyl titanate and 42.6 g of toluene were chargedinto a four-neck flask of 1 liter provided with a thermometer, astirrer, a condenser and a water dividing unit, and were refluxed andcaused to react for 10 hours, while water produced was drained by usingthe water dividing unit.

Subsequently, 161.2 g (1.49 mol) of benzyl alcohol, 179.0 g (1.49 mol)of diethylene glycol monomethyl ether were added to the resultantproduct, and were refluxed and caused to react for 11 hours, while waterproduced was drained.

The removal of the residual solvent and residual alcohol by desolvationand steam distillation gave a target product of the composition shown inB-5 of Table 1, at a yield of 100%.

Production Example 6 (Plasticizer Shown in B-6 of Table 1)

A target product shown in B-6 of Table 1 was obtained at a yield of 100%in the same way as that of Production example 5 except that the amountof ethylene glycol was changed to 105.5 g (1.7 mol), the amount ofbenzyl alcohol was changed to 102.7 g (0.95 mol), and the amount ofdiethylene glycol monomethyl ether was changed to 114.1 g (0.95 mol).

TABLE 1 Plasticizer of the component (B) (B-1) (B-2) (B-3) (B-4) (B-5)(B-6) (I-1) (mass %) 50 50 100 67 — — (II-1) (mass %) 25 40 0 33 — —(III-1) (mass %) 25 10 0 0 — — Ratio of n = 0 — — — — 55 23 (mass %)Ratio to (I-1) — — — — 55 54 adipic (mass %) acid (II-1) — — — — 23 26esters (mass %) of (III-1) — — — — 22 20 n = 0 (mass %)

The (B-5) includes the adipic acid esters (n=0) of the formulae (I-1),(II-1) and (III-1) and includes the following formulae (IV-1), (V-1) and(VI-1) as residues.

The (B-6) includes the adipic acid esters (n=0) of the formulae (I-1),(II-1) and (III-1) and includes the following formulae (IV-2), (V-2) and(VI-2) as residues.

Each of the numeric values in the general formulae (IV-1), (V-1),(VI-1), (IV-2), (V-2) and (VI-2) represents an average degree ofcondensation (N) when preparing a mixture of the adipic acid esters ofn=0 and n=1-5 in the general formulae (IV), (V) and (VI).

Each average degree of condensation (N) was obtained from an ester valuemeasured by the following method.

About 1 g of sample was weighed, to which 25 ml of a 0.5 mol/L KOHethanol solution was added, decomposed in a hot-water bath for one hour,and then the ester value was calculated from the amount of consumed KOHthrough the use of phenolphthalein as an indicator, by titrating theresultant product with a 0.5 mol/L hydrochloric acid aqueous solution.

The ester value is an mg value of potassium hydroxide required forsaponifying 1 g of sample and can be calculated by the followingequation:Ester value=number of ester bonds in one molecule×56.1×1000/molecularweight.

In the case of the general formula (IV), (V) or (VI), the number ofester bonds and the molecular weight can be calculated from its degreeof condensation, and thus an average degree of condensation N can becalculated from its ester value.

For example, since an average molecular weight of the general formula(IV) is 338.40+172.18×N and an average number of the ester bonds is2N+2, an ester value of the general formula (IV) can be obtained fromthe following equation.Ester value of the general formula(IV)=(2N+2)×56.1×1000/(338.40+172.18×N)

The plasticizers shown in B-5 and B-6 in Table 1 are mixtures of thegeneral formulae (IV), (V) and (VI), but their main ingredients areconsidered to be the general formula (IV), and thus the calculationexample was shown from the above-described equation as the generalformula (IV).

In the case of the plasticizer shown in B-5, the ester value is 392.2,and when N is calculated from the above-described equation, N is 0.45.

Additionally, a ratio of the adipic acid esters of n=0, and ratios ofthe adipic acid esters of the formulae (I), (II) and (III) in the adipicacid esters of n=0 were calculated by the above-mentioned GCmeasurement.

The component (B) for comparison: Trade name “DRA150” (triacetin)(diglycerine tetraacetate), manufactured by Daicel Corporation

Each evaluation test was carried out by the method described belowthrough the use of each composition in the Examples and a ComparativeExample. The results of the evaluations are shown in Table 2.

Each composition was stirred and mixed using a Henschel mixer so thatthe temperature was 70° C. or more by frictional heat in the mixer, thensupplied into a twin screw extruder (temperature of cylinder; 200° C.,temperature of die; 220° C.), and pelletized by extrusion.

The obtained pellets were supplied into an injection-molding machine,and test specimens were injection-molded under the condition of acylinder temperature of 200° C., a mold temperature of 50° C., and amolding cycle of 30 sec. (injection period; 15 sec. and cooling period;15 sec.) and were used for each evaluation test.

(MFR)

A measurement was carried out at 220° C., under a load of 10 kg on thebasis of ISO1133. It is indicated that the larger the MFR, the betterthe thermoplasticity.

(Nominal Tensile Strain)

A nominal tensile strain of the test specimen was measured in accordingwith ISO527 (unit of nominal tensile strain: %).

(Shock Resistance (Charpy))

A Charpy impact strength (kJ/m²) was measured in according withISO179/1eA (unit: kJ/m²).

(Mass Reduction Rate Under Heat and Humidity Conditions)

The cellulose acetate composition obtained by using “LABO PLASTOMILL”was molded using a press forming machine at a predetermined temperatureof 210° C. to produce a plate-like sample of 80×50×2 mm. A massreduction rate (reduction rate relative to mass after 24 hours) of theplate-like sample after leaving this plate-like sample to stand for 500hours in an atmosphere of 65° C. and 85% RH was obtained.

TABLE 2 Comparative Examples Example 1 2 3 4 5 6 1 (A) Cellulose ester100 100 100 100 100 100 100 (parts by mass) (B) (B-1) (parts by mass) 25(B-2) (parts by mass) 25 (B-3) (parts by mass) 25 (B-4) (parts by mass)25 (B-5) (parts by mass) 25 (B-6) (parts by mass) 25 Triacetin (parts bymass) 25 MFR (g/10 min), 220° C., 10 kg 15.2 16.2 19.7 23.0 11.1 7.9 2.9Nominal tensile strain (%) 14.3 13.5 14.4 13.5 13.5 14.1 8.7 Charpyimpact strength (KJ/m²) 10.3 10.0 11.0 10.5 9.7 6.2 5.1 Specific gravity1.28 1.28 1.28 1.28 1.29 1.29 1.30 Mass reduction rate under 0.5-1% lessless less less less 2-3% heat and humidity conditions than than thanthan than 0.5% 0.5% 0.5% 0.5% 0.5%

Examples 1-6 had higher MFR values than the value of Comparative Example1, thereby exhibiting a higher thermoplasticity. Particularly, thecomposition having a high content of the adipic acid ester of theformula (I) and low content of the adipic acid ester of the formula(III) exhibited a high thermoplasticity.

The invention claimed is:
 1. A cellulose ester composition comprising:(A) a cellulose ester and (B) a plasticizer, wherein the plasticizercontains the adipic acid ester of the following formula (I), a mixtureof the adipic acid esters of formulae (I) and (II) or a mixture of theadipic acid esters of formulae (I), (II) and (III),


2. The cellulose ester composition according to claim 1, which contains1-50 parts by mass of the plasticizer of the component (B) relative to100 parts by mass of the cellulose ester of the component (A).
 3. Thecellulose ester composition according to claim 1, wherein the celluloseester of the component (A) is selected from cellulose acetate, celluloseacetate propionate and cellulose acetate butylate.